6 inch scope; what can I see

[JOC]

It's also worth looking at truss tube versions of larger Dobs like my 8" - the reduction in size is quite useful when it comes to transport.

[jetstream]

Limiting Magnitude

Aperture (inches)	Aperture (mm)	Limiting Magnitude (method 1)	Limiting Magnitude (method 2)
1/4	6	7.5	6.3
.31	8	8.2	6.9
2	50.8	12.2	11.0
3	76.2	13.1	11.8
4	101.6	13.7	12.5
5	127.0	14.2	12.9
6	152.4	14.6	13.3
8	203.2	15.2	14.0
10	254.0	15.7	14.5
11	279.4	15.9	14.7
12	304.8	16.1	14.8
14	355.6	16.4	15.2
16	406.4	16.7	15.5
17	431.8	16.8	15.6
18	457.2	17.0	15.7
20	508.0	17.2	16.0
22	558.8	17.4	16.2
24	609.6	17.6	16.4
30	762.0	18.1	16.8
32	812.8	18.2	17.0
200	5080	22.2	21.0

Method 1 M_L= 3.7 + 2.5 * Log₁₀(D²)  where D = aperture in mm.
From "VISUAL ASTRONOMY FOR THE DEEP SKY" by Roger N. Clark.

Method 2 M_L= 9.5 + 5.0 * Log₁₀(D)  where D = aperture in inches.
From "THE OBSERVATIONAL AMATEUR ASTRONOMER" by Patrick Moore.

The differences in columns reflect differences in initial assumptions about
sky conditions, visual acuity and others.
Your results may vary.

Back to Magnification Calculator

 

This is a borrowed chart that I use to check my progress at times. Under my skies-good enough to see M33 naked eye- the 15" dob sits me in the middle between the two calculations, so far 15.7 mag or so.

The 6" will show you spiral arms in a few select galaxies-M51,M33 and M101 and this will need very dark skies, well over 21 mag IMHO. It will also show dust lanes in a few galaxies-the Needle,Andromeda and M82, maybe more.